The two drugs were more lethal in combination against cancer cells than when either drug was used alone.

'The combination of pimozide and mevastatin increased cancer cell death,' said UNSW researcher Louise Lutze-Mann, study co-author. 'We needed a lower dose of each drug to kill the same amount of cells.'

Researchers have also investigated the effects of olazapine, a 'second-generation' anti-psychotic drug, and found that it also kills cancer cells and has fewer side-effects.

It accumulates in the lung, which suggests that it may prove to be most useful in treating lung cancer.

The researchers are now testing these drugs on tumour cells from brain cancers since these tumours are extremely difficult to treat and are frequently associated with poor patient prognosis.

These finding were published in the International Journal of Cancer.